1. Field of the Invention
The present invention relates generally to the art of medical systems, and more specifically to managing data communications between multiple independent subsystems forming a safety critical system.
2. Description of the Related Art
Today's safety critical systems, such as automated medical system products or surgical equipment, may be constructed as a collection of independent components realized in hardware and software. Constructing a suite of independent components or modules affords medical system product designers and manufacturers the ability to create and deploy subsystems that perform specific functions that are a subset of the complete device or system.
Designs that take advantage of allocating functions to a plurality of specialized subsystems must include a communications mechanism to enable the subsystems to interact. Subsystems may share or communicate control and status information between each other to realize complete system functionality. These communications are typically implemented using a communications protocol that specifies a uniform or consensus format that the subsystems use to transmit and receive information to each other.
Traditionally, medical system products transmit control and status signals between subsystems over a fixed wire or cable using a standard cable interface, such as Universal Serial Bus, Ethernet, etc. Recent developments have made it highly desirable for subsystems to communicate over a wireless network, thus reducing or eliminating the need to use fixed wire cables or backplanes to connect subsystems.
Current wireless implementations based on the Bluetooth™ communications protocol can become unsuitable for interconnection of subsystems forming medical products that typically are interconnected using a fixed wire cable.
A major problem that may result in a hazardous situation when implementing the above-mentioned wireless Bluetooth communications protocol in a medical environment is a slave device subsystem. Such a slave device subsystem in a medical application may include a remote control mechanism or a foot pedal that may mistakenly connect to and unintentionally interact with a foreign or separate master instrument host subsystem. For example, a wireless foot pedal in operating theater A may pair and connect to instrument host A while a surgeon uses the foot pedal during the procedure to control instrument host A. During the conduct of this procedure, another surgeon activates wireless foot pedal in operating theater B and initiates the Bluetooth ‘pairing’ process. The wireless foot pedal in operating theater B pairs and connects to instrument host B and a surgeon uses the foot pedal during the procedure to control instrument host B.
However, a slave device, i.e. foot pedal, may pair with multiple master devices, i.e. instrument hosts, in a Bluetooth environment. In the foregoing example, the wireless foot pedal in operating theater B also pairs and connects with instrument host A. In this situation, the surgeon in operating theater B is controlling instrument hosts A and B simultaneously while the surgeon in operating theater A is also controlling instrument host A. The simultaneous operation of an instrument host from two wireless foot pedals can create confusion, disrupt a delicate operating procedure, and can potentially cause injury or even death to the patient in operating theater A. The surgeon in operating theater B may successfully control instrument host B in an effort to perform a procedure while unaware that he is simultaneously sending the same control input or signals to instrument host A. The surgeon in operating theater A may observe this interference, but remains unable to address the situation other than to discontinue the procedure, being forced to shut down instrument host A.
Overall system integrity is paramount to designing and deploying safety critical systems. Thus, today's designers are faced with a difficult and complex implementation challenge to ensure wireless communications between desired subsystems provide the required level of safety in an operating theater environment.
Furthermore, the communications protocol employed in the construction of safety critical systems must provide the ability for a slave device to exclusively pair and connect with a pre-selected master device ensuring the slave device is only communicating with a single master device at any given time.
Based on the foregoing, it would be advantageous to provide a wireless connection for use in safety critical systems that overcome the foregoing drawbacks present in previously known Bluetooth communications protocol designs used in the design of medical systems.